Method of manufacturing bi-layered ferroelectric thin film
A method of forming a Bi-layered ferroelectric thin film on a substrate with good reproducibility, using a mixed composition of a Bi-containing organic compound and a metal polyalkoxide compound by at least one technique selected from the group consisting of molecular deposition such as CVD, and spincoat-sintering.
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Claims
1. A method of producing a layered ferroelectric thin film containing bismuth on a substrate, comprising the steps of:
- mixing a Bi-containing organic compound and a metal alkoxide compound that comprises at least two different kinds of metal atoms; and
- forming a layered ferroelectric thin film containing bismuth on the substrate by a process including deposition of the mixture onto the substrate.
2. The method of claim 1, wherein said deposition is selected from the group consisting of molecular deposition, spincoat-sintering, and chemical vapor deposition.
3. The method of claim 1, wherein the formed Bi-layered ferroelectric thin film is described by the following Formula 1:
- Formula 1
4. The method of claim 1, wherein the metal alkoxide compound is described by the following Formula 2:
- Formula 2
5. The method of claim 1, wherein the deposition comprises chemical vapor deposition.
6. The method of claim 1, wherein the mixture comprises 1 to 99 weight % of the Bi-containing organic compound and 99 to 1 weight % of the metal alkoxide compound.
7. The method of claim 4, wherein each metal alkoxide compound of R.sub.j1, R.sub.j2,... R.sub.j6, R.sub.k1, R.sub.k2,... R.sub.k6 represented by Formula 2 comprises at least one of an ethyl group or an isopropyl group.
8. The method of claim 4, wherein A.sub.i of Formula 2 comprises at least one element selected from the group consisting of Sr and Ba; B.sub.j comprises at least one element selected from the group consisting of Nb and Ta; and B.sub.k comprises at least one element selected from the group consisting of Nb and Ta.
9. The method of claim 1, wherein the Bi-containing organic compound comprises at least one compound selected from the group consisting of Bi tertiary butoxide and Bi tertiary pentoxide.
10. The method of claim 5, wherein the chemical vapor deposition comprises dissolving the Bi-containing organic compound and the metal alkoxide compound in an organic solvent to form a solution; vaporizing the solution to form a gas; and applying the gas on the substrate.
11. The method of claim 10, wherein the organic solvent comprises tetrahydrofuran.
12. The method of claim 10, wherein the chemical vapor deposition comprises optical chemical vapor deposition to irradiate ultraviolet rays to the pyrolitic atmosphere of the source material gas.
13. The method of claim 10, wherein the chemical vapor deposition comprises plasma chemical vapor deposition to plasma-excite the gas when the gas is pyrolyzed.
14. The method of claim 2, wherein the spincoat-sintering comprises:
- dissolving the Bi-containing organic compound and the metal alkoxide compound in an organic solvent to form a solution;
- coating the solution on the substrate and drying the coating; and
- sintering the coating under an oxygen atmosphere.
15. The method of claim 14, wherein the organic solvent comprises tetrahydrofuran.
16. The method of claim 1, wherein an organic compound containing Pb is further added to the mixture.
17. The method of claim 16, wherein the amount of the Pb-containing organic compound is from 1.times.10.sup.-5 to 200 parts by weight when the mixed composition comprising Bi-containing organic compound and the metal polyalkoxide compound is 100 weight parts.
18. The method of claim 16, wherein the formed layered ferroelectric thin film is represented by the following Formula 3:
- Formula 3
19. The method of claim 16, wherein the layered ferroelectric thin film is applied on the substrate by chemical vapor deposition, using a mixture comprising an alkoxide compound represented by the following Formula 4 and a Pb-containing organic compound,
- Formula 4
20. The method of claim 16, wherein the Pb-containing organic compound comprises at least one compound selected from the group consisting of Pb tertiary butoxide and Pb oxotertiary butoxide.
21. The method of claim 16, wherein the Bi-containing organic compound comprises at least one compound selected from the group consisting of Bi tertiary butoxide and Bi tertiary pentoxide.
22. The method of claim 19, wherein the chemical vapor deposition comprises optical chemical vapor deposition to irradiate ultraviolet rays to the pyrolitic atmosphere of the gas.
23. The method of claim 19, wherein the chemical vapor deposition comprises plasma chemical vapor deposition to plasma-excite the gas when the gas is pyrolyzed.
24. The method of claim 1, wherein the substrate is a semiconductor.
25. The method of claim 1, wherein the layered ferroelectric thin film is 1 nm to 10.mu.m thick.
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Type: Grant
Filed: May 9, 1997
Date of Patent: Aug 3, 1999
Assignees: Matsushita Electronics Corporation (Osaka), Kojundo Chemical Laboratory Co., Ltd. (Saitama), Symetrix Corporation (Colorado Springs, CO)
Inventors: Yukoh Hochido, deceased (late of Tokyo), Hidekimi Kadokura (Tokyo), Masamichi Matsumoto (Saitama), Koji Arita (Colorado Springs, CO), Masamichi Azuma (Shiga), Tatsuo Otsuki (Fukui)
Primary Examiner: Shrive Beck
Assistant Examiner: Michael Barr
Law Firm: Merchant, Gould, Smith, Edell, Welter & Schmidt, P.A.
Application Number: 8/854,173
International Classification: B05D 512; B05D 312; C23C 1600;
